Answer: The side of the original square is 4 feet.
Step-by-step explanation:
Given , the sides of the original square is lengthened by 7 feet.
The area of the new square = 121 square feet.
Let the original side of square be<em> 'x'.</em>
The new side = <em>x+7</em>
Area of new square =(side)² = <em>(x+7)²</em>
As per given , we have
Taking square roots on both sides , we get
Hence, the side of the original square is 4 feet.